MKIII British Army Compass

[glenn baker]

Dear Sir, I am restoring 2 MK111 British Marching Compass,s.One is in perfict condition the other one is 95% for the RSL Museum in Leonora Western Australia. The fluid that they were filled with has evaporated.I am told that it was alchol but what type and percentage.
Regards All Glenn

[Battery Command Post]

Dear Sir, I am restoring 2 MK111 British Marching Compass,s.One is in perfict condition the other one is 95% for the RSL Museum in Leonora Western Australia. The fluid that they were filled with has evaporated.I am told that it was alchol but what type and percentage.
Regards All Glenn

I understand it was isopropyl alcohol (aka isopropanol) but I don't know what conc it would have been. Most restorers recommend purified kerosene as an alternative. I believe the instrument should be in a vacuum tank when the isopropyl alc is added. There is also, I believe, a hazard with restoring these instruments as they contain radioactive radium on the dials, but I'm sure you are aware of this.

Rob

[collector josh]

Hi all
Collecting and restoring compasses is an interesting and somewhat addictive passion, however... I see so many people with pre 1960s compasses with intentions of restoring them.
I myself own several compasses my favourite of witch is my 1942 T.G.Co WWII MKIII compass similar to the one described in the thread and I would like to inform people as to the dangers related to these compasses. These compasses like so many pre 1960's compasses contain radium 266, a radioactive isotope mixed with other compounds to form a paint used for the luminosity in the compass. As radium breaks down it turns a rusty brown colour and can be found on the dial and sighting line. Inhaling and injesting air born radium particles is potentially deadly and servicing such compasses should be left to the professionals. The worst thing anyone could do is open the dial chamber and contact the fluid inside. Doom and gloom aside these compasses are relatively safe to handle although regular contact is not recommended because of the radiation leaking from the case, radium 266 produces beta and gamma radiation . The beta radiation is contained within the case however the gamma leaks out and has been recorded at levels above 30usv/h, if this compass was in your pocket on a regular basis you would well and truly exceed the safe level recommendation for radiation exposure. I have linked a few websites for your viewing on the risks of collecting radium compasses. Radiation Risks Radium Girls - Wikipedia, the free encyclopedia